Finding the Fourth Proportional to 1,287.96, 1,930.34 and 556.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,287.96 : 1,930.34 = 556.72 : x
2. Step 2: Convert to fraction form
   1,287.96/1,930.34 = 556.72/x
3. Step 3: Cross multiply
   1,287.96x = 1,930.34 × 556.72
4. Step 4: Simplify right side
   1,287.96x = 1,074,658.88
5. Step 5: Solve for x
   x = 1,074,658.88/1,287.96
6. Step 6: Final answer
   x = 834.39